1. Field of The Invention
This invention relates generally to a leukocyte-removing filter and a leukocyte-removing apparatus furnished therewith. More specifically, it relates to a leukocyte-removing filter capable of removing leukocytes from a solution containing blood components while efficiently removing thrombocytes or blood platelets therefrom.
2. Description of The Prior Art
In recent years, blood transfusion has been changing from whole blood transfusion to component blood transfusion, so that a component medicine containing pure erythrocytes has been required. Generally, blood obtained from donors is fractionated into various components by centrifugation so that erythrocytic component is separated from other components in the form of a concentrated red cell, which will be hereinafter referred to as "CRC", to be transfused into patients who need erythrocytes. However, since such a CRC copiously contains other blood cells, such as leukocytes and thrombocytes, there are serious problems in that side effects tend to be caused by the components other than erythrocytes after transfusion. Particularly, side effects, such as nonhemolytic pyrogenic side effects, production of antileukocytic antibodies and graft v.s. host reaction, are often caused by leukocytes after transfusion. For that reason, leukocytes are usually removed from CRC by filtration. Furthermore, a case where transfusion is frequently repeated, it is desired to remove thrombocytes from CRC since it is required to prevent thrombocytes from producing antithrombocytic antibody.
Heretofore, in order to remove thrombocytes along with leukocytes, a filter of a small pore size (distances between fibers are small in a case where the filter comprises fibers) is used. However, when the pore size of the filter is decreased, the flow rate of blood passing through the filter decreases, so that there is the disadvantage in that the filtration and removal of leukocytes and thrombocytes take a long time.
It is therefore a principal object of this invention to provide a filter which can efficiently remove leukocytes together with thrombocytes by filtration or adsorption from a solution containing blood cells, such as CRC, and an apparatus furnished therewith.